Automatic-stoking spiral boiler.



' T. KUWADA.

AUTOMAHC STOKING SPIRAL BOILER.

APPLICATION FILED DEC. 4.1911- atented Jan. 21, 1919.

2 SHEETS-SHEET I.

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' constructed TOMOAKI KUWADA, OF AOYAMA, TOKYO, JAPAN.

AUTOMATIC-STOKING SPIRAL BOILER.

Specification of Letters Patent.

Patented Jan. 21, 1919.

Application filed December 4, 1917. Serial No. 205,312.

To all whom it may concern:

Be it known that I, T OMOAKI KUWADA, engineer, subject of the Emperor of Japan, residing at No. 15 Takagi-cho, Aoyama, Tokyo, Japan, have invented new and useful Im rovements in Automatic-Stoking Spiral Boilers, of which the following is a specification.

' This invention relates to an automatic stoking spiral boiler, which may be used as a steam boiler, steam-heater, hot air range, and the like, and which is composed of a centrally located coal-storing cylinder (cylindrical coal bunker), surrounded by a group of spiral water tubes alternately arranged with similarly shaped flues, all so that the burning gases ascending from the-furnace below ass through the said flues, transferring their heat to the water in the adjacent water tubes, and finally escaping intoa' smoke chamber provided on top; the said coal-storing cylinder is provided with a number of spirally cut slots to correspond with and fit to each of the flues, the slots normally facin the walls of the water tubes; the space inside the coalstoring cylinder and the flues bein thus partitioned the one from the other by the walls of the flues, but when necessary to clean the flues the latter are brought into free communication with the space inside the coal-storin cylinder by slightly rotating the said cylinc er.

The objects of the invention lie in increasing the heat-transferring efiiciency of the heating surface by making the flues in spiral fashion, in effecting the cleaning of the flues more easily, and also in attaining automatic stoking action by lettin the combustibles supplied to the coal-stor ng cylinder gradually fall as they burn.

With a view to attain the objects of this invention, types No. 1 and No. 2 have been designed, as illustrated in the appended drawings.

Figures 1 to 6 inclusive are drawings showing type No. 1, while Figs. 7 to 11 inclusive are those showing type No. 2.

Fig. 1 is a vertical section of the boiler.

Fig. 2 is a horizontal cross-section at 22 of Fig. 1.

' Fig. 3 is a horizontal cross-section of the same at 3-3.

Fig. 4 is a perspective view of the whole.

Fig. 5 shows an elemental segment forming the spiral water tubes.

Fig. 6 is a perspective view of the coalstoring cylinder.

Fig. 7 is a vertical section of the boiler.

Fig. 8 is a front elevation.

Fig 9 is a horizontal section at 9-9 of Fig.

Fig. 10 is a horizontal section at 10-10 of the same.

Fig. 11 shows a perspective view of the inside of the boiler.

In the above figures the same indices show the same parts.

The structure of this boiler may be divided into three parts, the furnace, the boiler proper, and the smoke chamber.

T 11 790 N 0. 1.-The boiler is constituted by a number of spirally bent. elementary segments (1. of the same shape, which are grouped together to form a cylindrical boiler. Each segment a has a water channel h of T-shaped cross-section. and orts b are provided at both the upper and ower ends and on both faces of the segment, so that when all the segments are grouped together all the parts will fit each other, making water-tight joints, the outer faces of the segments also making a continuous periphery and forming a: cylindrical space at the center, when the whole constitutes a set of spiral flues 71 formed by any two adjacent segments. The heating surface thus formed by the walls of the spiral flues 'z' is impinged upon by the gases of combustion ascending from below. Therefore, when compared with a simple vertically arranged heating surface,

the effectiveness of the heat transfer of the heating surface is considerably increased. In other words, by this method of construction a greatly increased heating surface can be obtained from a boiler of given volumetric dimensions.

Tightening bands 9 are employed at the upper and lower parts of the boiler in'a suitable manner, to tighten and retain the group of the segments a in their proper position. The coal-storing cylinder (cylindrical coal bunker) 0 is provided with a number of spirally cut slots j which are of the same shape as the spiral flues c. When the cylinder is inserted into the central space formed by the grou of segments. its spiral slots j exactl fit and face the walls forming the water tu es h and the flues z' are shut off from the central space by the peripheral wall of the coal-storing cylinder 0.

When the coal-storing cylinder 0 is slightly rotated, each of the spiral slots j coincides with each of the flues i, and the fines z are brought into free communication with the inside of the coal storing cylinder 0. Thus the communication between the fines i and the coal-storing cylinder 0 is obstructed, when fuel is-being fedinto the cylinder 0, and again that communication can be obtained by rotating the cylinder 0 a little, when it is desiredto clean the inside of the flues z. The coal-storing cylinder 0 is supported at the top, of the smoke chamber by means of a ring-shaped rim is, and a cover Z is provided on top of the cylinder, whereby the coal cylinder 0 can be easily rotated from outside, facilitating the feedg of ue as Well as, cl a i g the fi s ihe furnace is composed oftwo parts, an terv and, an inner casing The inner casing is supported ontop andinside of the outer casing in a suitable manner, and in turn supports the grate f. Around the outer casing and near theupper edge thereof are provided numerous ventilation holes 6, through wh ch. ir s admitted arol dv the heated portion surrounding the inner casing into he. f r a e fr m elow he gra e. fhe nace ybe onstruct d n the or inary fashion without any inner casing, as ho n by the illust at on Qfpe 2 0 1 The rr i io f a fi e-de m n sh-do s" n i ferent rom mmon furnaces. v

e. s te c b d s ocat d top of the boiler and embraces the upper opening of all the fines At the center is a circular hole to receive the coal-storing cylinder 0, and toward one side an exhaust port 0, leadn to h h m ey- Type No. 2 differs from type No. l in that the boiler proper of the latter is com- Pose of a gr up of le ent ry eg ts. each of which constitutes the water tubes 7b, whereas in the former the water tubes h and fines Yi -are constructed in a single solid body, forming an inside structure 9, al though of the same spiral shape; and this is inclosed by a boiler-drum p, the water being admitted into the space between this boiler-drum p and the inside structure 9. The aforementioned inclosing drum p may be dispensed with, and the spiral inside structure 9 alone may be immersed in water, thereby accomplishing the function of boiling the water.

Claims:

7 1. A boiler comprising a plurality of water tubes of spiral formation secured together in boiler formation to provide spiral flues and a central fuel receiving chamber, and a fuel storing member removably m unted n sa d h mbe and orm d. i l ts f p r m tion, hich coincide with said fines.

2, A boiler comprising a plurality of water tubes of spiral formation secured together in boiler formation to provide spiral flues and a central fuel receiving chamber, and a fuel storing member removably mounted in said chamber and formed with slots of spiral formation which correspond w th a d n d memb r ing t t bly mounted in said chamber and capable of occupying one position wherein said slots coincide with said flues'and another position 1yivherein said slots do not coincide with said ues.

3. A boilercomprising a plurality of water tubes arranged to form a central fuel receiving chamber, a plurality of spiral fiues, and a fuel storing member rotatably mounted in said chamber and capable of occupying two positions, said member being formed with slots corresponding to said tubes whereby said member covers or uncovers said flues according as it occupies one position or the other.

In testimony whereof I have signed my name to this specification.

TOMOAKI KUWADA,

Copies of this patcntmay be'obtained for five cents each, by addressingthe Commis sipner of -1Batents,

Washington, 15. C. 

